Glass wafers or substrates in semiconductor applications are known to provide many advantages over other wafer materials. These advantages include, for example, high resistivity and low RF coupling to devices. Also, during manufacturing processes, glass wafers do not heat up as much as other types of wafers and, hence do not succumb to a degraded quality factor to the extent of other wafer materials.
However, in order to use glass wafers for device fabrication, it is necessary to have special tools for material handling. This results in many constraints such as, for example, cost and unnecessary downtime for conventional semiconductor fabrication automated handling tooling, which cannot process glass wafers.
For example, conventional semiconductor fabrication automated handling tooling are specifically designed for silicon based wafers, which may have wafer identification alphanumerics and machine readable bar codes on their back sides. These tools shine light on the wafer to verify that the wafer is present. In addition, these tools also assist in the proper and accurate alignment of the wafer, so the wafer can undergo subsequent processing. By way of illustration, the automated handling tooling will transport the wafer from one processing tool to another processing tool, e.g., a processing chamber to a lithography machine (e.g., stepper). By shining light onto the wafer, the presence of the wafer can be detected or the wafer backside bar code may be read. Also, by the use of alignment marks and/or identification marks, the automated handling tooling can verify wafer identification and proper alignment is achieved in all axes, i.e., x-y-z axes.
The conventional semiconductor fabrication automated handling tooling, though, cannot perform these same functions with glass substrates. Specifically, as the glass substrate is transparent, the automated handling tooling cannot detect the presence of the glass substrate. Also, the automated handling tooling cannot identify the glass substrate.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.